This invention relates to an improved device for cathodic protection of dissimilar metals on heat exchangers for fresh water cooling of marine engines.
As is well known, internal combustion engines are frequently employed for powering watercraft. It is the normal practice, particularly in connection with inboard engines, that engine coolant water is cooled by circulating the hot water through a heat exchanger secured to the exterior of the hull using flanges. Sea water cools the hot engine water while contained within the heat exchanger thereby providing cooler water which is then recirculated back to the engine, see, for example, U.S. Pat. 4,991,546 which is incorporated by reference.
These heat exchanges are very helpful, but difficulty has existed in the flange attachment for a double-hulled ship, because of corrosion. The present invention has been developed to reduce corrosion and improve cathodic protection for the flange used to secure the heat exchanger outlet to a vessel.
The invention relates to a cooling system for a fresh water cooled marine engine, comprising of a heat exchanger disposed in seawater for cooling heated fresh water from a marine engine; an inlet to said heat exchanger for receiving heated fresh water from said marine engine; an outlet from said heat exchanger for discharging cooled fresh engine water from said heat exchanger; said outlet having a central conduit, a gasket, a flange, a plurality of studs and a bushing; said outlet passing through a hull of a vessel; and said studs being covered by a bushing having a tube and a faceplate
The invention also relates to a vessel having a marine engine is provided with which fresh water is used as coolant for the engine and then circulated by means of cooling pump to a heat exchanger. Heated fresh water is passed from the engine into a conduit to the heat exchanger by means of this pump. The pump delivers the hot water to an inlet for the engine heat exchanger, as which is affixed to the hull of the boat. A flange is used to secure the inlet conduit. The heated fresh water circulates through an external heat exchanger, which cools the hot water by exposure to seawater in which the engine water heat exchanger is located.
The heated fresh engine water does not mix in the seawater in which the vessel is operating and once cooled, the cooled fresh water is circulated back into the engine through a second port, which is flanged, to the hull.
The present invention relates to an improved flange construction for use to and from the heat exchanger having a unique bushing for securing the flange to the hull.
It is an object of this invention to provide an improved cooling system for a marine engine that will be easily installed in single or double hulled vessels to reduce corrosion and still insure a proper and good seal between the heat exchanger and the hull.